Refrigerator

ABSTRACT

A motor driving device for a refrigerator is disclosed. The refrigerator includes a condenser to condense refrigerant, a fan module mounted to one surface of the condenser so as to blow air; a first circuit unit including a microprocessor to output a speed command signal and a filter unit connected to an output terminal of the microprocessor so as to filter the output speed command signal; and a second circuit unit including an inverter controller to output an inverter switching control signal on the basis of the filtered speed command signal and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to a fan motor contained in the fan module. Thus, when the motor is driven, noise is greatly reduced.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2010-0088551, filed on Sep. 9, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerator, and more particularly to a refrigerator for reducing noise generated when a fan motor is driven.

2. Description of the Related Art

Generally, a refrigerator stores foodstuffs (hereinafter, referred to as “stored goods”) in a fresh state for a long time using cool air. The refrigerator includes a freezing chamber for storing the stored goods at a temperature below zero, a refrigerating chamber for storing the stored goods at a temperature above zero, and a cooling cycle for cooling the freezing chamber and the refrigerating chamber, and further includes a controller for controlling the freezing chamber, the refrigerating chamber, and the cooling cycle.

The kitchen is considered to be an important life space where members of a family have a meal and talk to each other about a matter of concerns, it is necessary for a refrigerator serving as the most important element of the kitchen to be gradually increased in size, and functional changes of the refrigerator are needed in a manner that members of a family can easily and conveniently use the refrigerator.

As the function of the refrigerator becomes complicated and the size of the refrigerator becomes enlarged, many developers and companies are more intensively conducting into various methods for reducing power consumption of the refrigerator and improving the efficiency of the refrigerator.

Therefore, various methods for effectively operating the fan or compressor contained in the refrigerator have been intensively researched by many developers and companies.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a refrigerator for reducing noise generated when the fan motor is driven.

It is another object of the present invention to provide a refrigerator for easily implementing noise reduction.

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a refrigerator including a condenser to condense a refrigerant; a fan module mounted to one surface of the condenser so as to blow air; a first circuit unit including a microprocessor to output a speed command signal and a filter unit connected to an output terminal of the microprocessor so as to filter the output speed command signal; and a second circuit unit including an inverter controller to output an inverter switching control signal on the basis of the filtered speed command signal and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to a fan motor contained in the fan module.

In accordance with another aspect of the present invention, a refrigerator includes a condenser to condense a refrigerant; a fan module mounted to one surface of the condenser so as to blow air; a first circuit unit including a microprocessor to output a speed command signal; and a second circuit unit including a noise reduction unit to reduce noise of the speed command signal, an inverter controller to output an inverter switching control signal on the basis of the noise-reduced speed command signal, and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to a fan motor contained in the fan module.

In accordance with another aspect of the present invention, a refrigerator includes a fan motor; a first circuit unit including a microprocessor to output a speed command signal and a filter unit connected to an output terminal of the microprocessor so as to filter the output speed command signal; and a second circuit unit including a noise reduction unit to reduce noise of the filtered speed command signal, an inverter controller to output an inverter switching control signal on the basis of the noise-reduced speed command signal, and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to the fan motor.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a refrigerator according to one embodiment of the present invention;

FIG. 2 is a block diagram showing an internal configuration of the refrigerator of FIG. 1;

FIG. 3 shows the inside a machine space of a refrigerator according to one embodiment of the present invention;

FIG. 4 is an exploded perspective view illustrating a fan module and a condenser of a refrigerator according to one embodiment of the present invention;

FIG. 5 is a block diagram illustrating constituent elements of the refrigerator shown in FIG. 1;

FIG. 6 is a circuit diagram illustrating a fan motor driver of a refrigerator according to one embodiment of the present invention;

FIG. 7 is a circuit diagram illustrating internal constituent elements of the inverter controller shown in FIG. 6;

FIG. 8 is a circuit diagram illustrating a first circuit unit and a second circuit unit for use in the fan motor driver shown in FIG. 6; and

FIGS. 9( a) and 9(b) are graphs illustrating noise reduction of the noise reduction unit shown in FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below with reference to the attached drawings.

The terms “module” and “unit” used to signify components are used herein to aid in understanding of the components and thus they should not be considered as having specific meanings or roles. Accordingly, the terms “module” and “unit” may be used interchangeably.

FIG. 1 shows a refrigerator according to one embodiment of the present invention.

Referring to FIG. 1, a refrigerator 1 according to an exemplary embodiment of the present invention has an outer appearance schematically formed by a case 110 having an internal space partitioned into a freezing chamber and a refrigerating chamber, a freezing chamber door 120 for shielding the freezing chamber, and a refrigerating chamber door 140 for shielding the refrigerating chamber.

Door handles 121 are provided at front surfaces of the freezing chamber door 120 and refrigerating chamber door 140 in such a manner that they are protruded from the front surfaces. The user may readily grasp the door handles 121 to pivot the freezing chamber door 120 and refrigerating chamber door 140.

On the other hand, a home bar 180, for convenience, may further be provided at the front surface of the refrigerating chamber door 140 to enable the user to remove a food stored in the refrigerating chamber, such as a beverage, without opening the refrigerating chamber door 140.

A dispenser 160, for convenience, may further be provided at the front surface of the freezing chamber door 120 to enable the user to easily take out ice or water without opening the freezing chamber door 120. A control panel 200 may be provided at an upper side of the dispenser 160 to control a driving operation of the refrigerator 1 and display the state of the refrigerator 1 in operation on a screen.

The control panel 200 may include an input unit 220 consisting of a plurality of buttons, and a display unit 230 for displaying a control picture, an operating state, etc.

The display unit 230 displays a control picture, an operating state, and information such as an internal temperature of the refrigerator. For example, the display unit 230 may display a service type (cubed ice, water, crushed ice or the like) of the dispenser, a set temperature of the freezing chamber, and a set temperature of the refrigerating chamber.

This display unit 230 may be implemented in various forms including a liquid crystal display (LCD), a light emitting diode (LED) display, and an organic light emitting diode (OLED) display. Also, the display unit 230 may be implemented in the form of a touch screen that can also perform the function of the input unit 220.

The input unit 220 may include a plurality of manipulating buttons. For example, the input unit 220 may include a dispenser setting button (not shown) for setting a service type (cubed ice, water, crushed ice or the like) of the dispenser, a freezing chamber temperature setting button (not shown) for setting the temperature of the freezing chamber, and a refrigerating chamber temperature setting button (not shown) for setting the temperature of the refrigerating chamber. Also, the input unit 220 may be implemented in the form of a touch screen that can also perform the function of the display unit 230.

Here, it will be understood that the refrigerator according to the present embodiment is not limited to a double door type shown in FIG. 1, but may be applied to any type including a one door type, a sliding door type, and a curtain door type. The refrigerator according to the present embodiment can also be applied to all kinds of refrigerators, each of which includes a compressor and fan for a refrigerating cycle or freezing cycle.

FIG. 2 is a block diagram showing an internal configuration of the refrigerator of FIG. 1.

Referring to FIG. 2, the refrigerator 1 includes a compressor 112; a condenser 116 for condensing the compressed refrigerant received from the compressor 112; a refrigerating chamber 122 installed in the refrigerating chamber (not shown) and a freezing chamber evaporator 124 installed in the freezing chamber (not shown) so as to evaporate the condensed refrigerant received from the condenser 116; a three-way valve 130 for providing the refrigerant condensed by the condenser 116 to the refrigerating chamber evaporator 122 or the freezing chamber evaporator 124; a refrigerating chamber expansion valve 132 for expanding the refrigerant provided to the refrigerating chamber evaporator 122; and a freezing chamber expansion valve 134 for expanding the refrigerant provided to the freezing chamber evaporator 124.

In addition, the refrigerator 1 may further include a liquid/gas separator (not shown) for separating refrigerant received from the evaporators 122 and 124 into liquid and gas.

The refrigerator 1 may further include a refrigerating chamber fan 142 for providing cool air received from the refrigerating chamber evaporator 122 to the refrigerating chamber (not shown), and a freezing chamber fan 144 for providing cool air received from the freezing chamber evaporator 122 to the freezing chamber (not shown).

In addition, the refrigerator 1 may further include a compressor driver 114 for driving the compressor 112, a refrigerating chamber fan driver 143 for driving the refrigerating chamber fan 142, and a freezing chamber fan driver 145 for driving the freezing chamber fan 144.

FIG. 3 shows the inside a machine space of the refrigerator according to one embodiment of the present invention.

Referring to FIG. 3, a machine space 110 a including constituent components of a freezing cycle may be located below the case 110 of the refrigerator 1.

The machine space 110 a of the refrigerator 1 includes the compressor 112 for compressing refrigerant, a fan module 115 for moving air, and the condenser 116 for condensing the refrigerant.

The compressor 112, the fan module 115, and the condenser 116 may be arranged in parallel at the top surface of a lower part of the case 110. Preferably, from the rear view of the case 110, the compressor 112, the fan module 115, and the condenser 116 are sequentially arranged from the left side of FIG. 3.

The fan module 115 is coupled to one end of the condenser 116 such that the fan module 115 and the condenser 116 are integrated into one module. The compressor 112 is located apart from the integrated module of the fan module 115 and the condenser 116. A partition (not shown) for partitioning the space into several spaces may be located between the compressor 112 and the fan module 115.

The condenser 116 is coupled to the top surface of the lower part of the case 116. The fan module 115 coupled to one end of the condenser 116 need not be separately coupled to the case 110. Preferably, the compressor 112 may be coupled to the top surface of the lower part of the case 110.

The air may be blown from the fan module 115 to the condenser 116 or may be blown from the condenser 116 to the fan module 115 in such a manner that heat exchange between the air and the refrigerant occurs in the condenser 116. However, the compressor 112 generates high-temperature heat, such that the fan module 115 may allow air to blow from the condenser 116 to the fan module 115, and may feed back the resultant air to the condenser 116.

FIG. 4 is an exploded perspective view illustrating the fan module and the condenser of the refrigerator according to one embodiment of the present invention.

Referring to FIG. 4, the refrigerator 1 includes the condenser 116 arranged below the case 110 in such a manner that a refrigerant pipe 116 a in which the refrigerant flows is stacked in a screw shape; the fan module 115 for allowing air to blow in a screw-shaped axis direction A formed by the refrigerant pipe 116 a of the condenser 116; and a fan bracket 117 for coupling the fan module 115 to one end of the condenser 116.

The refrigerant compressed in the compressor 112 flows in the refrigerant pipe 116 a of the condenser 116, and the refrigerant pipe 116 a is stacked in a screw shape. The refrigerant pipe 116 a is bent in a straight state such that it is stacked in a screw shape. Multiple circular-shaped heat sink pins 116 b are coupled to the outside of the refrigerant pipe 116 a in the direction perpendicular to the refrigerant flowing direction. The heat sink pins 116 b are mounted to the outside of the refrigerant pipe 116 a through spot welding.

The condenser 116 may include the refrigerant pipe bracket 116 c inserted into some parts of the heat sink pins 116 b located at an upper part in such a manner that the outer appearance of the refrigerant pipe 116 a stacked in a screw shape can be maintained. The condenser 116 may include a condenser support 119 coupled to some parts of the heat sink pins 116 b located at a lower part in such a manner that the bottom of the condenser 116 is coupled to the top surface of the case 110.

The fan module 115 is coupled to one side of the condenser 116 by the fan bracket 117 in such a manner that the air blows in a screw-shaped axis direction A formed by the refrigerant pipe 116 a.

The fan module 115 includes a fan 115 a for enabling the air to blow by rotation, a fan motor 115 c for rotating the fan 115 a, and a fan housing 115 b coupled to the fan motor 115 c to support the fan 115 a and coupled to the fan bracket 117.

Preferably, the center point of the fan 115 a may be located at the screw-shaped axis direction A formed by the refrigerant pipe 116 a. The fan housing 115 b may be screw-coupled to the fan bracket 117 through a screw 115 d. In this case, an elastic body 115 e formed of rubber, resin or metal is located between the fan housing 115 b and the fan bracket 117, such that it prevents vibration of the fan module 115 from being applied to the condenser 116.

The fan bracket 117 couples the fan module 115 to one side of the condenser 116. Preferably, the fan bracket 117 may be coupled to the fan housing 115 b by the screw 115 d. The fan bracket 117 includes the curved condenser connection part 117 a in such a manner that a cross section of the condenser connection part 117 a is semi-circled in response to the outer appearance of the heat sink pin 116 b. The condenser connection part 117 a of the fan bracket 117 is inserted into some parts of the heat sink pins 116 b arranged at one side of the condenser 116.

FIG. 5 is a block diagram illustrating constituent elements of the refrigerator shown in FIG. 1.

Referring to FIG. 5, the refrigerator shown in FIG. 3 includes a compressor 112, a refrigerating chamber fan 142, a freezing chamber fan 144, a controller 310, and a temperature sensing unit 320. In addition, the refrigerator may further include a compressor driver 113, a refrigerating chamber fan driver 143, a freezing chamber fan driver 145, a machine space fan 115, a machine space fan driver 400, and an input unit 220.

Detailed description of the compressor 112, the refrigerating chamber fan 142, and the freezing chamber fan 144 has already been disclosed in FIG. 2.

The input unit 220 includes a plurality of operation buttons, such that it transmits freezing and refrigerating chamber setting temperatures entered by the user to the controller 310.

The temperature sensing unit 320 detects a temperature of the refrigerator and transmits a signal regarding the detected temperature to the controller 310. In this case, the temperature sensing unit 320 detects a refrigerating chamber temperature and a freezing chamber temperature.

In order to control the on/off operations of the compressor 112 and the fan 142 or 144, the controller 310 may control the compressor 112 and the fan 142 or 144 by directly controlling the compressor driver 113 and the fan driver 143 or 145, as shown in FIG. 5. In this case, the fan driver may be the refrigerating chamber fan driver 143 or the freezing chamber fan driver 145.

For example, the controller 310 includes a microprocessor such that it may output a speed command signal to each of the compressor driver 113 and the fan driver (143, 145 or 400). If the speed command signal of the present embodiment is a PWM-based signal, the drive device according to the embodiment of the present invention can transmit the speed command signal to the machine space fan driver 400 without generating any noise, and a detailed description thereof will hereinafter be described with reference to FIGS. 6 to 9.

The compressor driver 113 includes a motor (not shown) for the compressor, the refrigerating fan driver 143 includes a motor (not shown) for the refrigerating chamber fan, and the freezing chamber driver 145 includes a motor (not shown) for the freezing chamber fan. Each motor is operated at a target rotation speed under the control of the controller 310.

The machine space fan driver 400 includes a motor 115 c for the machine space fan. The machine space fan motor 115 c is operated at a target rotation speed under the control of the controller 310, and a detailed description thereof will hereinafter be described with reference to FIGS. 6 to 9.

Provided that the motor is a three-phase motor, the three-phase motor may be controlled by the switching operation of the inverter (not shown) or may be constantly controlled using AC power. In this case, each motor (not shown) may be any one of an inductor motor, a blushless DC (BLDC) motor, or a synchronous reluctance motor (synRM).

The controller 310 not only controls the compressor 112 and the fan (142, 144, or 115) as described above, but also controls the operations of the refrigerator 1. That is, the controller 310 may control a refrigerant cycle in response to a set temperature received from the input unit 220.

For example, the controller 310 may not only control the compressor driver 113, the refrigerating chamber fan driver 143, the freezing chamber fan driver 145, and the machine space fan driver 400, but also control the three-way valve 130, the refrigerating chamber expansion valve 132, and the freezing chamber expansion valve 134. In addition, the controller 310 may further control the condenser 116 and the display unit 230.

As can be seen from FIGS. 2 and 5, evaporators 122 and 124 are respectively mounted to the refrigerating chamber and the freezing chamber, the fan 142 and the driver 143 are used for the refrigerating chamber evaporator 122, and the fan 144 and the driver 145 are used for the freezing chamber evaporator 124. However, the scope or spirit of the present invention is not limited thereto, a common evaporator (not shown) may also be used for the refrigerating and freezing chambers as necessary, and a common fan (not shown) and a common driver (not shown) may also be used for the refrigerating and freezing chambers. In this case, a damper (not shown) may be installed between the refrigerating chamber and the freezing chamber. The fan (not shown) may compulsorily ventilate cool air generated from one evaporator such that the cool air may be blown to the freezing and refrigerating chambers.

The fan driver of the refrigerator according to the embodiment of the present invention may be identical to the machine space fan driver 400 for driving the fan motor 115 c of the machine space fan module 115 for cooling the machine space 110 a. In addition, the fan driver may also be applied to the refrigerating chamber fan driver 143 for driving the motor of the refrigerating chamber fan 142 or the freezing chamber fan driver 145 for driving the motor of the freezing chamber fan 144.

FIG. 6 is a circuit diagram illustrating a fan motor drive unit of a refrigerator according to one embodiment of the present invention.

Referring to FIG. 6, the fan motor drive unit 400 of the refrigerator may include a converter 410, an inverter 420, an inverter controller 430, a DC-terminal voltage detector B, a smoothing capacitor C, and an output current detection unit E. In addition, the drive unit 220 may further include an input current detection unit A, a reactor L, and the like.

The reactor L is arranged between a commercial AC power source (vs) 405 and the converter 410 so that it performs power factor correction or a step-up (or boost) operation. In addition, the reactor L may also limit harmonic current caused by the high-speed switching of the converter 410.

An input-current detector A may detect an input current (i_(s)) received from the AC power source 405. In order to detect the input current (i_(s)), a current sensor, a current transformer (CT), a shunt resistor, etc. may be used as the input-current detector A. The detected input current (i_(s)) is a pulse-shaped discrete signal, and may be input to the controller 430.

The converter 410 converts the commercial AC power 405 passing through the reactor L into DC power, and outputs the DC power. Although the commercial AC power 405 of FIG. 4 is shown as single-phase AC power, it should be noted that the commercial AC power 405 may also be three-phase AC power as necessary. The internal structure of the converter 410 may be changed according to types of the commercial AC power 405.

Meanwhile, the converter 410 may be comprised of a diode and the like, such that it may also perform a rectifying operation without any additional switching operation.

For example, provided that the commercial AC power 405 is single-phase AC power, four diodes may be bridged to one another. Provided that the commercial AC power 405 is three-phase AC power, 6 diodes may be bridged to one another.

For example, provided that the commercial AC power 405 is single-phase AC power, a half-bridge converter wherein two switching elements and four diodes are connected to one another may be employed. Provided that the commercial AC power 405 is three-phase AC power, 6 switching elements and 6 diodes may be employed.

The converter 410 may include one or more switching elements, such that it can perform a boosting operation, power factor improvement, and DC-power conversion by the switching operation of the corresponding switching elements.

The smoothing capacitor C is connected to an output terminal of the converter 410. The smoothing capacitor C smooths the converted DC power output from the converter 410, and stores the smoothed DC power. Although the smoothing capacitor C is comprised of only one element in FIG. 5, it may also be comprised of a plurality of elements as necessary to guarantee device stability.

For convenience of description, although the smoothing capacitor C is connected to an output terminal of the converter 410, the scope of the smoothing capacitor C is not limited thereto and DC power may be directly input to the smoothing capacitor C. For example, DC power from a solar cell may be directly input to the smoothing capacitor C, or may be DC/DC converted and input to the smoothing capacitor C. The following description will focus only upon constituent elements shown in the drawings.

DC power is stored at both ends of the smoothing capacitor C, so that both ends may be referred to as a DC terminal or a DC link terminal.

The DC-terminal voltage detector B may detect a DC-terminal voltage (Vdc) at both ends of the smoothing capacitor C. For this operation, the DC-terminal voltage detector B may include a resistor, an amplifier, and the like. The detected DC-terminal voltage (Vdc) is a pulse-shaped discrete signal, and may be input to the inverter controller 430.

The inverter 420 includes a plurality of inverter switching elements, converts the DC power smoothed by on/off operation of the switching elements into three-phase AC power (va, vb, vc) of a predetermined frequency, and outputs the resultant three-phase AC power (va, vb, vc) to a three-phase motor 230.

The inverter 420 may include upper-arm switching elements (Sa, Sb, Sc) and lower-arm switching elements (S′a, S′b, S′c). In more detail, the inverter 220 includes a total of three pairs (Sa&S′a, Sb&S′b, Sc&S′c) of upper-arm and lower-arm switching elements, wherein the three pairs (Sa&S′a, Sb&S′b, Sc&S′c) are connected to one another in parallel. In addition, one upper-arm switching element (Sa, Sb or Sc) is connected in series to one lower-arm switching element (S′a, S′b or S′c) such that one pair (Sa&S′a, Sb&S′b or Sc&S′c) of upper-arm and lower-arm switching elements is formed. One diode is connected in inverse parallel to one switching element (Sa, S′a, Sb, S′b, Sc or S′c).

The switching elements contained in the inverter 420 receive an inverter switching control signal (Sic) from the inverter controller 430, such that on/off operations of the individual switching elements are performed on the basis of the inverter switching control signal (Sic). As a result, a three-phase AC power having a predetermined frequency is output to the three-phase synchronous motor 230.

The inverter controller 430 may control the switching operation of the inverter 420. For this operation, the inverter controller 430 may receive an output current (i_(o)) detected by the output current detection unit E as an input.

The inverter controller 430 may output the inverter switching control signal (Sic) to the inverter 420 so as to control the switching operation of the inverter 420. The inverter switching control signal (Sic) may be a PWM switching control signal, and is generated and output on the basis of the output current value (i_(o)) detected by the output current detection unit E. The output of the inverter switching control signal (Sic) will hereinafter be described with reference to FIG. 7.

The output current detection unit (E) detects an output current (i_(o)) flowing between the inverter 420 and the three-phase motor 230. In other words, the output current detection unit (E) may detect current flowing in the motor 230. The output current detection unit E may detect all output currents (i_(a), i_(b), i_(c)) of individual phases, or may also detect a two-phase output current using three-phase equilibrium.

The output current detection unit (E) may be located between the inverter 420 and the motor 230. For current detection, a current transformer (CT), a shunt resistor, or the like may be used as the output current detection unit (E).

When using the shunt resistor, three shunt resistors may be located between the inverter 420 and the synchronous motor 230, or may be coupled to one end of each of the three lower-arm switching elements (S′a, S′b, S′c) of the inverter 420. Meanwhile, two shunt resistors may be used using three-phase equilibrium. In contrast, when using only one shunt resistor, a corresponding shunt resistor may be arranged between the above-mentioned capacitor C and the inverter 420.

The detected output current (i_(o)) serving as a pulse-shaped discrete signal may be input to the inverter controller 430, and an inverter switching control signal (Sic) may be generated on the basis of the detected output current (i_(o)). For convenience of description and better understanding of the present invention, it is assumed that the detected output current (i_(o)) is three-phase output current (ia, ib, ic).

The three-phase motor 230 includes a stator and a rotor. AC power of each phase having a predetermined frequency is applied to a coil of a stator of each phase (a-, b-, or c-phase) such that the rotor starts rotating.

Various types of motors 230 may be used, for example, a Surface-Mounted Permanent-Magnet Synchronous Motor (SMPMSM), an Interior Permanent Magnet Synchronous Motor (IPMSM), a Synchronous Reluctance Motor (Synrm), etc. SMPMSM or IPMSM may be a Permanent Magnet Synchronous Motor (PMSM), and Synrm has no permanent magnet.

If the converter 410 includes one or more switching elements, the inverter controller 430 may control the switching operation of the switching element contained in the converter 410. For this operation, the inverter controller 430 may receive the input current (i_(s)) detected by the input current detection unit A. The inverter controller 430 may output a converter switching control signal (Scc) to the converter 410 to control the switching operation of the converter 410. The converter switching control signal (Scc) may be a PWM switching control signal, and may be generated and output on the basis of the input current (i_(s)) detected by the input current detection unit A.

FIG. 7 is a circuit diagram illustrating internal constituent elements of the inverter controller shown in FIG. 6.

Referring to FIG. 7, the inverter controller 430 includes a first axis transformation unit 510, a velocity calculation unit 520, a current command generator 530, a voltage command generator 540, a second axis transformation unit 550, and a switching control signal output unit 560.

The axis transformation unit 510 receives three-phase output current (ia, ib, ic) detected by the output current detection unit E, and converts the three-phase output current (ia, ib, ic) into two-phase current (iα, iβ) of a stationary reference frame (also called a stationary coordinate system).

The axis transformation unit 510 may convert the two-phase current (iα, iβ) of the stationary reference frame into a two-phase current (id, iq) of a rotation coordinate system.

The velocity calculation unit 520 may calculate the position ({circumflex over (θ)}r) and speed ({circumflex over (ω)}r) on the basis of the two-phase current (iα, iβ) received from the axis transformation unit 510.

On the other hand, the velocity calculation unit 520 may calculate the position ({circumflex over (θ)}r) and the speed ({circumflex over (ω)}r) on the basis of the rotor position signal (H).

The current command generator 530 generates a current command value (i*_(q)) on the basis of the calculated speed ({circumflex over (ω)}r) and the speed command value (ω*_(r)). For example, the current command generator 530 enables the PI controller 535 to perform Proportional Integral (PI) control on the basis of a difference between the calculated speed ({circumflex over (ω)}r) and the speed command value (ω*_(r)), such that it can generate the current command value (i*_(q)). Although the q-axis current command value (i*_(q)) has been exemplary used as a current command value in FIG. 5, it should be noted that a d-axis current command value (i*_(d)) may also be generated simultaneously with the q-axis current command value (i*_(q)). In contrast, the d-axis current command value (i*_(d)) may be set to zero (0).

In the meantime, the current command generator 530 may further include a limiter (not shown) preventing a level of each current command value (i*_(q)) from exceeding an allowed range.

The voltage command generator 540 generates d-axis and q-axis voltage command values (v*_(d) and v*_(q)) on the basis of not only the d-axis and q-axis currents (i_(d) and i_(g)) axis-transformed to a two-phase rotation coordinate system but also the current command values and (i*_(d) and i*_(q)) from the current command generator 530. For example, the voltage command generator 540 enables the PI controller 544 to perform PI control on the basis of a difference between the q-axis voltage current value (i_(q)) and the q-axis current command value (i*_(q)), such that it can generate the q-axis voltage command value (v*_(q)). In addition, the voltage command generator 540 enables the PI controller 544 to perform PI control on the basis of a difference between the d-axis current value (i_(d)) and the d-axis command value (i*_(d)), such that it can generate the d-axis voltage command value (v*_(d)). In the meantime, the voltage command generator 540 may further include a limiter (not shown) preventing a level of each voltage command value (v*_(d) or v*_(q)) from exceeding an allowed range.

The generated d-axis and q-axis voltage command values (v*_(d) and v*_(q)) may be input to the axis transformation unit 550.

The axis transformation unit 550 may receive the position ({circumflex over (θ)}r) calculated by the velocity calculation unit 520 and the d-axis and q-axis voltage command values (v*_(d) and v*_(q)), and may then perform axis transformation of the received signals ({circumflex over (θ)}_(r), v*_(d) and v*_(q)).

First, the axis transformation unit 550 may convert a two-phase rotation coordinate system into a two-phase stationary coordinate system. In this case, the axis transformation unit 550 may use the position signal ({circumflex over (θ)}r) calculated by the velocity calculation unit 520.

In addition, the axis transformation unit 550 may convert the two-phase stationary coordinate system into a three-phase stationary coordinate system. By the above-mentioned transformation, the axis transformation unit 550 may output three-phase output voltage command values (v*_(a), v*_(b), v*_(c)).

The switching control signal output unit 560 may generate and output a switching control signal (Sic) for a PWM inverter on the basis of the three-phase output voltage command values (v*_(a), v*_(b), v*_(c)).

The output inverter switching control signal (Sic) may be converted into a gate drive signal by a gate driver (not shown), so that it may be input to a gate of each switching element contained in the inverter 420. As a result, individual switching elements (Sa, S′a, Sb, S′b, Sc, S′c) contained in the inverter 420 may perform the switching operation.

FIG. 8 is a circuit diagram illustrating a first circuit unit and a second circuit unit for use in the fan motor driver shown in FIG. 6. FIGS. 9( a) and 9(b) are graphs illustrating noise reduction of the noise reduction unit shown in FIG. 8.

Referring to FIG. 8, the first circuit unit 610 may include a microprocessor 612, a filter unit 615, and a connection unit 618.

The microprocessor 612 may output the speed command signal S1 of the fan motor 230. For example, the microprocessor 612 may output a speed command signal S1 of the fan motor 230 in consideration of a set temperature and a current temperature of the refrigerator. The microprocessor may be contained in the controller 310 of FIG. 5.

On the other hand, the speed command signal S1 may be a PWM-based signal. For example, as the speed command value for increasing a rotation speed of the fan motor 230 becomes higher, the pulse width of the speed command signal S1 becomes wider. In contrast, as the speed command value becomes smaller, the pulse width of the current command signal S1 becomes narrower. In this case, the magnitude of the speed command signal S1 may be constant.

The filter unit 615 is coupled to the output terminal of the microprocessor 612 so as to perform filtering of the current command signal S1. For example, if a high frequency noise such as the switching noise is coupled to the speed command signal S1, the filter unit 615 may include at least one resistor element and at least one capacitor element. In this case, capacitance of the capacitor element may be limited to 1 μF or less.

As can be seen from FIG. 8, one resistor R1 and one capacitor C1 are connected in series such that an RC filter is configured. Therefore, the speed command signal S1 may reduce noise by filtering the speed command signal S1. The noise-reduced speed command signal is input to the connection unit 618 such that it can be transmitted to the second circuit unit 620. The connection unit 618 may be implemented as a connector.

The first circuit unit 610 and the second circuit unit 620 may be implemented as different circuit boards. In this case, the first circuit unit 610 and the second circuit 620 may be interconnected by a transmission unit 640 such as a cable. For example, the first circuit unit 610 may be arranged on the top surface of the refrigerator 1. The second circuit unit 620 may be arranged on the back surface of the refrigerator 1. In this case, the length of the transmission unit 640 may be about 2˜3 meters.

Due to a difference in length between the first circuit unit 610 and the second circuit unit 620, the refrigerator according to the related art converts a PWM-based speed command signal into a PAM-based speed command signal, and transmits the PAM-based speed command signal to the second circuit unit 620. For the above-mentioned operation, a buck converter or the like has been used.

However, the buck converter has a disadvantage in that it requires additional power consumption and additional costs. In order to solve such problems, the refrigerator according to the present embodiment directly outputs a PWM-based speed command signal without using an additional conversion unit such as the buck converter, and applies the output signal of the filter unit 615 to an output terminal of the microprocessor 612 so as to reduce noise of the speed command signal. As a result, the refrigerator according to the present embodiment can reduce noise while the motor is driven, and can also implement noise reduction through a simple circuit.

The second circuit unit 620 may include an inverter 420, an inverter controller 430, a noise reduction unit 625, and a connection unit 628.

The inverter 420 performs the switching operation in response to the PWM-based inverter switching control signal (Sic) received from the inverter controller 430, such that it converts the input DC power (Vdc) into AC power having a predetermined frequency and outputs the predetermined-frequency AC power. As a result, the fan motor 230 is driven.

The inverter controller 430 outputs the inverter switching control signal (Sic) on the basis of the speed command signal received from the first circuit unit 610. The operations of the inverter controller 430 will hereinafter be described with reference to FIG. 7.

The inverter 420 and the inverter controller may be implemented as one module, which may be referred to as an intellectual power module (IPM) 630. For example, the IPM 630 receives a PWM-based speed command value ((ω*_(r)), an output current (io), operation power (Vcc), etc., and performs internal signal processing, such that it may output a three-phase AC current (u,v,w-phase current or a,b,c-phase current) and the like.

The IPM 630 may further include a voltage regulator (not shown), a charge pump circuit (not shown), etc. to operate the switching elements (Sa, Sb, Sc, S′a, S′b, S′c) of the inverter 420.

The noise reduction unit 625 may reduce noise of the filtered speed command signal S2 received through the connection unit 628. For example, if a high-frequency noise such as peak noise is coupled to the filtered speed command signal S2, the noise reduction unit 625 may include at least one resistor element to reduce the high-frequency noise. Preferably, impedance of the resistor element may be in the range from 1 kΩ to 10 kΩ. In addition, the noise reduction unit 625 may further include at least one capacitor element.

Only one resistor element R2 is exemplary shown in FIG. 8. The resistor element R2 may be used to reduce noise of the filtered speed command signal. The noise-reduced speed command signal S3 may be input to the inverter controller 430.

FIG. 9( a) exemplary shows the speed command signal S2 located prior to the input of the noise reduction unit 625. The speed command signal S2 is output from the microprocessor 612 contained in the first circuit unit 610, and is then received through the transmission unit 640, such that peak noise (Sp1, Sp2) may occur. In the meantime, the speed command signal S2 is a PWM-based signal such that the pulse width (W1 or W2) of the speed command signal S2 may be changed in response to the speed command value.

FIG. 9( b) exemplary shows the speed command signal S3 generated from the noise reduction unit 625. The speed command signal S3 is input to the resistor element R2 of the noise reduction unit 625 such that peak noise (Sp1, Sp2) and the like may be removed. Therefore, the motor can be driven without any noise. In addition, a malfunction of the motor startup operation is prevented from being generated.

On the other hand, device stability of a circuit element contained in the inverter controller 430 or a circuit element contained in the inverter 630 may be improved.

The first circuit unit 610 may simultaneously output not only the PWM-based speed command signal but also the operation power (Vcc) for operating the second circuit unit 620 to the second circuit unit 620.

The operation power may be used as power for operating the IPM 630 of the second circuit unit 620, and may be input to the second circuit unit 620 through one terminal of the IPM 630. The operation power may be in the range from 12V to 16V. Preferably, the operation power may have a constant DC voltage level. On the other hand, the PWM-based speed command signal may have a DC power level of about 5V.

Although not shown in the drawings, the operation power may be input to the connection unit 618 of the first circuit unit 610 and be input to the connection unit 628 of the second circuit unit 620.

Preferably, the above-mentioned operation power may be transferred through a path different from that of the PWM-based speed command signal. That is, although the operation power is transferred to the second circuit unit 620 through the connection units 618 and 628, it should be noted that the operation power may also be transferred to the second circuit unit 620 through different terminals.

The refrigerator according to the foregoing exemplary embodiments is not restricted to the exemplary embodiments set forth herein. Therefore, variations and combinations of the exemplary embodiments set forth herein are fall within the scope of the present invention. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made without departing from the spirit and scope of the present invention as defined by the following claims.

As is apparent from the above description, the refrigerator according to the embodiments of the present invention removes a high frequency component by filtering a PWM speed current command signal generated from a microprocessor using a filter unit, resulting in a reduction in noise of the speed command signal.

The refrigerator can easily implement the filter unit using resistor and capacitor elements, resulting in the occurrence of no high frequency components.

The noise reduction unit for use in the refrigerator is arranged prior to the inverter, resulting in a reduction in peak noise of the current command signal.

The noise reduction unit for use in the refrigerator can be easily implemented with resistor elements for reducing peak noise.

The PWM current command signal generated from the microprocessor is directly input to the inverter without pulse amplitude modulation (PAM) processing, resulting in a reduction in production costs.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

What is claimed is:
 1. A refrigerator comprising: a condenser to condense a refrigerant; a fan module mounted to one surface of the condenser so as to blow air; a first circuit unit including a microprocessor to output a speed command signal and a filter unit connected to an output terminal of the microprocessor so as to filter the output speed command signal; and a second circuit unit including an inverter controller to output an inverter switching control signal on the basis of the filtered speed command signal and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to a fan motor contained in the fan module.
 2. The refrigerator according to claim 1, wherein: the condenser is formed by screw-stacking a refrigerant pipe in which the refrigerant flows; and the fan module is configured to blow air in a screw-shaped axis direction foamed by the refrigerant pipe of the condenser.
 3. The refrigerator according to claim 1, wherein the filter unit includes at least one resistor element and at least one capacitor element.
 4. The refrigerator according to claim 1, wherein the second circuit unit further includes a noise reduction unit to reduce noise of the filtered speed command signal.
 5. The refrigerator according to claim 4, wherein the noise reduction unit includes at least one resistor element.
 6. The refrigerator according to claim 3, wherein the capacitor element has capacitance of less than 1 μF.
 7. The refrigerator according to claim 5, wherein the resistor element contained in the noise reduction unit has impedance of 1 kΩ˜10 kΩ.
 8. The refrigerator according to claim 1, wherein the filtered speed command signal is a PWM-based signal.
 9. The refrigerator according to claim 1, wherein the inverter controller includes: a velocity calculation unit to calculate speed on the basis of an output current flowing in the fan motor; a current command generator to generate a current command value on the basis of the calculated speed and the speed command signal; a voltage command generator to generate a voltage command value on the basis of the current command value and an output current flowing in the motor; and a switching control signal output unit to output the PWM-based switching control signal on the basis of the voltage command value.
 10. The refrigerator according to claim 1, wherein the first circuit unit further outputs operation power of the second circuit unit.
 11. The refrigerator according to claim 1, wherein the first circuit unit and the second circuit unit are implemented as separate circuit boards spaced apart from each other.
 12. A refrigerator comprising: a condenser to condense a refrigerant; a fan module mounted to one surface of the condenser so as to blow air; a first circuit unit including a microprocessor to output a speed command signal; and a second circuit unit including a noise reduction unit to reduce noise of the speed command signal, an inverter controller to output an inverter switching control signal on the basis of the noise-reduced speed command signal, and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to a fan motor contained in the fan module.
 13. The refrigerator according to claim 12, wherein: the condenser is formed by screw-stacking a refrigerant pipe in which the refrigerant flows; and the fan module is configured to blow air in a screw-shaped axis direction formed by the refrigerant pipe of the condenser.
 14. The refrigerator according to claim 12, wherein the noise reduction unit includes at least one resistor element.
 15. The refrigerator according to claim 14, wherein the resistor element contained in the noise reduction unit has impedance of 1 kΩ˜10 kΩ.
 16. The refrigerator according to claim 12, wherein the speed command signal is a PWM-based signal.
 17. The refrigerator according to claim 12, wherein the inverter controller includes: a velocity calculation unit to calculate speed on the basis of an output current flowing in the fan motor; a current command generator to generate a current command value on the basis of the calculated speed and the speed command signal; a voltage command generator to generate a voltage command value on the basis of the current command value and an output current flowing in the motor; and a switching control signal output unit to output the PWM-based switching control signal on the basis of the voltage command value.
 18. The refrigerator according to claim 12, wherein the first circuit unit further outputs operation power of the second circuit unit.
 19. The refrigerator according to claim 12, wherein the first circuit unit and the second circuit unit are implemented as separate circuit boards spaced apart from each other.
 20. A refrigerator comprising: a fan motor; a first circuit unit including a microprocessor to output a speed command signal and a filter unit connected to an output terminal of the microprocessor so as to filter the output speed command signal; and a second circuit unit including a noise reduction unit to reduce noise of the filtered speed command signal, an inverter controller to output an inverter switching control signal on the basis of the noise-reduced speed command signal, and an inverter to convert an input DC power into a predetermined-frequency AC power by performing a switching operation in response to the inverter switching control signal and to output the AC power to the fan motor. 